Plumbing is a system of pipes, drains, fittings, valves, and fixtures installed for the distribution of potable water for drinking, heating and washing, and waterborne waste removal. Plumbing originated during ancient civilizations such as the Greek, Roman, Persian, Indian, and Chinese civilizations as the needed to provide potable water and wastewater removal for larger numbers of people grew. In particular, the need to drain waste water such as greywater or sullage has become ubiquitous in civilized countries around the world. Greywater or sullage is all wastewater generated in households or commercial buildings that does not contain fecal contamination, and may have sources such as sinks, showers, baths, clothes washing machines and dish washers.
Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements.